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Author Ruelle, J.; Yamamoto, H.; Thibaut, B.
Title Growth Stresses and Cellulose Structural Parameters in Tension and Normal Wood from Three Tropical Rainforest Angiosperm Species Type Journal Article
Year 2007 Publication BioResources Abbreviated Journal (up) BioResources
Volume 2 Issue 2 Pages 235-251
Keywords Cellulose; Microfibril angle; Crystallite size; Tension wood; Tropical rainforest; Growth stresses
Abstract Few studies have been conducted about relation between cellulose parameters and biomechanical properties of wood in tropical angiosperms species. For this purpose, on 13 trees from 3 species of French Guyana tropical rainforest in a clear active process of restoring verticality, i) growth strains were measured in situ in order to determine the occurrence of tension wood within samples and ii) cellulose structural parameters were estimated on all the samples using X-ray diffraction method. Crystallite size was estimated from the full-width at half-maximum of the Miller index (002) arc diffraction and angle T was measured following Cave's method. Relationships between these parameters and growth stresses were good and the variations between normal and tension wood were significant, i. e. a lower angle T and a larger crystallite size in tension wood. In order to have a good estimation of the microfibril angle in the main layer of the secondary wall for each species, an experimental calibration was done between angle T and microfibril angle observed with scanning electron microscopy.
Address [Ruelle, Julien; Thibaut, Bernard] UMR EcoFoG, Kourou 97387, Guyana, Email: ruelle_j@kourou.cirad.fr
Corporate Author Thesis
Publisher NORTH CAROLINA STATE UNIV DEPT WOOD & PAPER SCI Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1930-2126 ISBN Medium
Area Expedition Conference
Notes ISI:000263689300009 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 122
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Author Wagner, F.; Rutishauser, E.; Blanc, L.; Herault, B.
Title Effects of Plot Size and Census Interval on Descriptors of Forest Structure and Dynamics Type Journal Article
Year 2010 Publication Biotropica Abbreviated Journal (up) Biotropica
Volume 42 Issue 6 Pages 664-671
Keywords Amazonia; biomass fluxes; coefficient of variation; forest permanent plots; turnover rates; WinBUGS
Abstract This study was designed to explicitly formulate the effect of census interval and plot size on the variability of descriptors of tropical forest structure (stand density, basal area, aboveground biomass [AGB]) and dynamic (tree growth, mortality and recruitment rates, biomass fluxes). A unique dataset from a broad plot network (37.5 ha) surveyed every 2 yr over a 16-yr period was used to develop and parameterize a new statistical model predicting the coefficients of variation for each forest descriptor. More than 90 percent of the inherent variability of these coefficients was predicted using a simple model including plot size and census interval in a Bayesian modeling framework. All descriptors of forest structure varied by <10 percent for plot sizes 42 ha. Among the descriptors of forest dynamics, AGB loss was the most variable. The number of 6.25 ha plots required to estimate its mean, over a 16-yr period, within a 20 percent error of the mean remains above four. This contrasts with a relative constant flux of biomass entering the plot through tree growth and tree recruitment. Tree growth was remarkably well estimated with <15 percent variability for a 2-yr census in a plot of 2 ha. This study provides an easy method to assess dataset limitations in efforts to estimate descriptors of forest structure and dynamic, which is of primary importance to decipher any clear consequences of global change in tropical forests.
Address [Wagner, Fabien; Herault, Bruno] Univ Antilles Guyane, UMR Ecol Forets Guyane, Kourou 97379, French Guiana, Email: bruno.herault@ecofog.gf
Corporate Author Thesis
Publisher WILEY-BLACKWELL PUBLISHING, INC Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0006-3606 ISBN Medium
Area Expedition Conference
Notes ISI:000283949700006 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 16
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Author Vantaux, A.; Roux, O.; Magro, A.; Ghomsi, N.T.; Gordon, R.D.; Dejean, A.; Orivel, J.
Title Host-Specific Myrmecophily and Myrmecophagy in the Tropical Coccinellid Diomus thoracicus in French Guiana Type Journal Article
Year 2010 Publication Biotropica Abbreviated Journal (up) Biotropica
Volume 42 Issue 5 Pages 622-629
Keywords ants; ladybird; mimicry; parasite; Wasmannia auropunctata
Abstract A variety of arthropods, particularly insects, have developed myrmecophilous interactions with ants to gain access to resources and/or for protection. Among these myrmecophiles, only a few examples have been documented in the Coccinellidae, most of them involving species able to feed on ant-tended Hemiptera. We report here a new case of obligate myrmecophily in the coccinellid Diomus thoracicus. Larvae are invariably and exclusively found in the nests of the ant Wasmannia auropunctata and seem to rely on ant brood as their only food source. Not only do ant workers show no aggressiveness toward the D. thoracicus larvae in their behavioral interactions at the colonial level, but also at the species level; while coccinellid adults are always attacked. The integration of the larvae inside of the ant nests is based on their chemical mimicry of the host's cuticular cues. Therefore, given the presence of the D. thoracicus larvae inside of the ant's nest, their predation on Wasmannia brood and their chemical mimicry, this species can be considered a specific parasite of W. auropunctata. Overall, this new case of myrmecophily not only specifically involves a highly invasive ant species, but also provides insights into the evolution of myrmecophily and myrmecophagy in coccinellids.
Address [Vantaux, Amelie; Magro, Alexandra; Orivel, Jerome] Univ Toulouse, UPS, EDB Lab Evolut & Diversite Biol, F-31062 Toulouse, France, Email: orivel@cict.fr
Corporate Author Thesis
Publisher WILEY-BLACKWELL PUBLISHING, INC Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0006-3606 ISBN Medium
Area Expedition Conference
Notes ISI:000281707700025 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 27
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Author Ruiz-Gonzalez, M.X.; Corbara, B.; Leroy, C.; Dejean, A.; Orivel, J.
Title The Weaver Wasp: Spinning Fungus into a Nest Type Journal Article
Year 2010 Publication Biotropica Abbreviated Journal (up) Biotropica
Volume 42 Issue 4 Pages 402-404
Keywords Allomerus decemarticulatus; French Guiana; Hirtella physophora; nest architecture; Nitela constructor; wasp biology
Abstract Wasp nests range from simple to complex structures made of paper or mud. Here, we show that a Neotropical wasp of the genus Nitela builds its nest entirely by weaving endophytic fungal hyphae and spider silk harvested from the leaves growing in the understory of the rain forest in French Guiana.
Address [Ruiz-Gonzalez, Mario X.; Orivel, Jerome] Univ Toulouse, UPS, EDB, Lab Evolut & Divers Biol, F-31062 Toulouse, France, Email: orivel@cict.fr
Corporate Author Thesis
Publisher WILEY-BLACKWELL PUBLISHING, INC Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0006-3606 ISBN Medium
Area Expedition Conference
Notes ISI:000279438900002 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 54
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Author Baraloto, C.; Couteron, P.
Title Fine-scale Microhabitat Heterogeneity in a French Guianan Forest Type Journal Article
Year 2010 Publication Biotropica Abbreviated Journal (up) Biotropica
Volume 42 Issue 4 Pages 420-428
Keywords canopy gap; geostatistics; light availability; microclimate; soil moisture; soil nutrients; topography
Abstract We examined fine-scale heterogeneity of environmental conditions in a primary rain forest in French Guiana to describe variation in microhabitats that plants may experience during establishment. We characterized both the range as well as the spatial structuring of 11 environmental factors important for seedling establishment in six hexagonal sampling grids, one each in gap and understory sites at three points representing the predominant geomorphic units in this primary forest. Each grid contained 37 sampling points separated by 31 cm-20 m. Monte-Carlo tests of semivariograms against complete spatial randomness indicated that for many variables in all six sampling grids, spatial dependence did not exceed 1 m. A principal component analysis of all sampling points revealed a lack of spatial microhabitat structure, rather than homogeneous patches associated with canopy structure or geomorphology. Our results suggest that ample fine-scale spatial heterogeneity exists to support the coexistence of plant species with differential abiotic requirements for regeneration.
Address [Baraloto, Christopher] INRA, UMR Ecol Forets Guyane, F-97387 Kourou, France, Email: chris.baraloto@ecofog.gf
Corporate Author Thesis
Publisher WILEY-BLACKWELL PUBLISHING, INC Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0006-3606 ISBN Medium
Area Expedition Conference
Notes ISI:000279438900005 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 55
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Author Paine, C.E.T.; Harms, K.E.; Schnitzer, S.A.; Carson, W.P.
Title Weak competition among tropical tree seedlings: Implications for species coexistence Type Journal Article
Year 2008 Publication Biotropica Abbreviated Journal (up) Biotropica
Volume 40 Issue 4 Pages 432-440
Keywords Brosimum alicastrum; competitive irrelevance; maintenance of biodiversity; Matisia cordata; resource competition; Panama; Peru; Pouteria reticulata; zone of influence
Abstract The intensity of competition among forest tree seedlings is poorly understood, but has important ramifications for their recruitment and for the maintenance of species diversity. Intense competition among seedlings could allow competitively dominant species to exclude subordinate species. Alternatively, the low density and small stature of forest tree seedlings could preclude intense interseedling competition. In this case, other processes, such as size-asymmetric competition with adults, interactions with consumers, or neutral dynamics would prevail as those structuring the forest understory. We tested the intensity of, and potential for, intraspecific competition among tree seedlings of three species (Brosimum alicastrum, Matisia cordata, and Pouteria reticulata) in two Neotropical rain forests. We reduced stem densities by up to 90 percent and monitored individual growth and survival rates for up to 24 mo. Individual growth and survival rates were generally unrelated to stem density. Contrary to the predicted behavior of intensely competing plant populations, the distribution of individual heights did not become more left-skewed with time for any species, regardless of plot density; i.e., excesses of short, suppressed individuals did not accumulate in high-density plots. We further measured the overlap of zones of influence (ZOIs) to assess the potential for resource competition. Seedling ZOIs overlapped only slightly in extremely dense monodominant plots, and even less in ambient-density plots of mixed composition. Our results thus suggest that interseedling competition was weak. Given the low density of tree seedlings in Neotropical forests, we infer that resource competition among seedlings may be irrelevant to their recruitment.
Address [Paine, C. E. Timothy; Harms, Kyle E.] Louisiana State Univ, Dept Biol Sci, Baton Rouge, LA 70803 USA, Email: cetpaine@gmail.com
Corporate Author Thesis
Publisher BLACKWELL PUBLISHING Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0006-3606 ISBN Medium
Area Expedition Conference
Notes ISI:000257717500006 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 134
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Author Degen, B.; Roubilk, D.W.
Title Effects of animal pollination on pollen dispersal, selfing, and effective population size of tropical trees: A simulation study Type Journal Article
Year 2004 Publication Biotropica Abbreviated Journal (up) Biotropica
Volume 36 Issue 2 Pages 165-179
Keywords Amazon; bees; Brazil; Dipteryx; Jacaranda; model; pollination; sensitivity analysis; trees
Abstract Animals, especially insects, are principal pollen vectors of tropical trees and have behavior patterns that affect gene dispersal. Here, we explore complex pollination systems using a new simulation model Eco-Gene and considering, among other factors, flowering synchrony. spatial distribution of trees, degree of selfing, population densities, pollinator flight distances, pollen deposition, and pollinator response to floral display size. Sensitivity analyses using two contrasting tree data sets (Jacaranda copaia and Dipteryx odorata) determined the importance of each parameter on three response variables: the proportion of seeds from self-pollination, effective population size, and pollen dispersal. Spatial considerations and attractiveness of floral displays were prominent features determining the population genetic result of pollinators, and some biological implications of the results are discussed.
Address INRA, Kourou 97387, French Guiana, Email: degen_b@kourou.cirad.fr
Corporate Author Thesis
Publisher ASSOC TROPICAL BIOLOGY INC Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0006-3606 ISBN Medium
Area Expedition Conference
Notes ISI:000222092900006 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 264
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Author Baraloto, C.; Molto, Q.; Rabaud, S.; Herault, B.; Valencia, R.; Blanc, L.; Fine, P.V.A.; Thompson, J.
Title Rapid simultaneous estimation of aboveground biomass and tree diversity across neotropical forests: A comparison of field inventory methods Type Journal Article
Year 2013 Publication Biotropica Abbreviated Journal (up) Biotropica
Volume 45 Issue 3 Pages 288-298
Keywords Biodiversity assessment; carbon stocks; Monitoring; Permanent plot; Survey; Tropical rain forest
Abstract A standardized rapid inventory method providing information on both tree species diversity and aboveground carbon stocks in tropical forests will be an important tool for evaluating efforts to conserve biodiversity and to estimate the carbon emissions that result from deforestation and degradation (REDD). Herein, we contrast five common plot methods differing in shape, size, and effort requirements to estimate tree diversity and aboveground tree biomass (AGB). We simulated the methods across six Neotropical forest sites that represent a broad gradient in forest structure, tree species richness, and floristic composition, and we assessed the relative performance of methods by evaluating the bias and precision of their estimates of AGB and tree diversity. For a given sample of forest area, a 'several small' (< 1 ha) sampling strategy led to a smaller coefficient of variation (CV) in the estimate of AGB than a 'few large' one. The effort (person-days) required to achieve an accurate AGB estimate (< 10% CV), however, was greater for the smallest plots (0.1 ha) than for a compromise approach using 0.5 ha modified Gentry plots, which proved to be the most efficient method to estimate AGB across all forest types. Gentry plots were also the most efficient at providing accurate estimates of tree diversity (< 10% CV of Hill number). We recommend the use of the 0.5 ha modified Gentry plot method in future rapid inventories, and we discuss a set of criteria that should inform any choice of inventory method. © 2012 The Author(s) Journal compilation © 2012 by The Association for Tropical Biology and Conservation.
Address Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian, EH26 0QB, United Kingdom
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 00063606 (Issn) ISBN Medium
Area Expedition Conference
Notes Export Date: 16 May 2013; Source: Scopus; Coden: Btroa; :doi 10.1111/btp.12006; Language of Original Document: English; Correspondence Address: Baraloto, C.; INRA, UMR 'Ecologie des Forêts de Guyane', 97387, Kourou Cedex, French Guiana; email: chris.baraloto@ecofog.gf Approved no
Call Number EcoFoG @ webmaster @ Serial 485
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Author Biwolé, A.B.; Dainou, K.; Fayolle, A.; Hardy, O.J.; Brostaux, Y.; Coste, S.; Delion, S.; Betti, J.L.; Doucet, J.-L.
Title Light Response of Seedlings of a Central African Timber Tree Species, Lophira alata (Ochnaceae), and the Definition of Light Requirements Type Journal Article
Year 2015 Publication Biotropica Abbreviated Journal (up) Biotropica
Volume 47 Issue 6 Pages 681-688
Keywords biomass allocation; Central Africa; light requirement: Lophira alata; population; relative growth rate; seedling growth; timber species; Afrique centrale; allocation de biomasse; besoins en lumière; croissance des semis; bois d'œuvre; Lophira alata; population; taux de croissance relatif
Abstract Light is of primary importance in structuring tropical tree communities. Light exposure at seedling and adult stages has been used to characterize the ecological profile of tropical trees, with many implications in forest management and restoration ecology. Most shade-tolerance classification systems have been proposed based on empirical observations in a specific area and thus result in contradictions among categories assigned to a given species. In this study, we aimed to quantify the light requirements for seedling growth of a Central African timber tree, Lophira alata (Ochnaceae), taking into account effects of population origin. In two controlled experiments: a light response experiment and a comparative population experiment, conducted in southwestern Cameroon, using seeds collected from four populations (three from Cameroon and one from Gabon), we examined the quantitative responses to irradiance of seedlings. After 2 years, mortality was very low (<3%), even in extremely low irradiance. Growth and biomass allocation patterns varied in response to light, with intermediate irradiance (24–43%) providing optimal conditions. Light response differed between populations. The Boumba population in the northeastern edge of the species' distribution exhibited the highest light requirements, suggesting a local adaptation. As a result of positive growth at low irradiance and maximum growth at intermediate irradiance, we concluded that L. alata exhibits characteristics of both non-pioneer and pioneer species. Implications of our results to propose an objective way to assign the light requirement for tropical tree species are discussed.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1744-7429 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number EcoFoG @ webmaster @ Serial 648
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Author Houadria, M.; Salas-Lopez, A.; Orivel, J.; Blüthgen, N.; Menzel, F.
Title Dietary and Temporal Niche Differentiation in Tropical Ants-Can They Explain Local Ant Coexistence? Type Journal Article
Year 2015 Publication Biotropica Abbreviated Journal (up) Biotropica
Volume 47 Issue 2 Pages 208-217
Keywords Ants; Baiting; Dietary specialization; Functional traits; Niche breadth; Partitioning; Temporal distribution
Abstract How species with similar ecological requirements avoid competitive exclusion remains contentious, especially in the species-rich tropics. Niche differentiation has been proposed as a major mechanism for species coexistence. However, different niche dimensions must be studied simultaneously to assess their combined effects on diversity and composition of a community. In most terrestrial ecosystems, ants are among the most abundant and ubiquitous animals. Since they display direct, aggressive competition and often competitively displace subordinate species from resources, niche differentiation may be especially relevant among ants. We studied temporal and trophic niche differentiation in a ground ant community in a forest fragment in French Guiana. Different baits were presented during day and night to assess the temporal and dietary niches of the local species. They represented natural food resources such as sugars, carrion, excrements, seeds, and live prey. In addition, pitfalls provided a background measure of ant diversity. The communities attracted to the different baits significantly differed from each other, and even less attractive baits yielded additional species. We detected species specialized on living grasshoppers, sucrose, seeds, or dead insects. Community-level differences between day and night were larger than those between baits, and many species were temporally specialized. In contrast to commonness, foraging efficiency of species was correlated to food specialization. We conclude that many ant species occupy different temporal or dietary niches. However, for many generalized species, the dietary, and temporal niche differentiation brought forward through our sampling effort, cannot alone explain their coexistence.
Address Department of Biology, Technical University of DarmstadtDarmstadt, Germany
Corporate Author Thesis
Publisher Place of Publication Editor
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Notes Export Date: 17 March 2015 Approved no
Call Number EcoFoG @ webmaster @ Serial 585
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